Friday, February 10, 2006

Infrared missile disrupter

The threat to passenger planes posed by shoulder-launched missiles is a big concern to the airline industry. But Lawrence Livermore National Laboratory (LLNL) in California, US, has come up with a novel way to jam this type of weapon.

Surface-to-air missiles can be fired in the general direction of a plane, and will use an infrared sensor in their nose to home in on the heat produced by a jet's engines.

Military planes can escape incoming heat seekers by launching decoys flares to fool the weapon's heat sensors. For commercial airliners, however, it's impractical to carry an arsenal of flammable decoys for every take off.

The LLNL defence system relies on a laser to produce a rapid stream of picosecond pulses at an infrared wavelength. The pulses are fed through a crystal to generate harmonic distortion and the original and the distorted beams are recombined to create even more distortion across many infrared frequencies.

This distorted signal can be beamed in the direction of any incoming missile (detected by an airliner's radar). The pulsed infrared should blind and confuse the missile's sensor, causing it to veer off target. And the beam ought to pose no danger to other aircraft, because it is beyond the range of human vision.